The networking of electrical devices within buildings is becoming increasingly important. Systems for monitoring room temperatures, air humidity, water discharge, etc., for example, already exist for this purpose. Several conventional applications automatically transmit measurement data to a power supply company. In addition, some applications already exist which provide for monitoring the activity of a person by analyzing device usage activity. In this regard, it can be monitored whether a kettle, a coffee maker, a washing machine or the like are regularly put into operation, for example. If such a device is not activated for a relatively long period of time, it stands to reason that a person living in such a household has deviated from his/her routine habits and, therefore, can possibly need outside assistance. The electrical devices can be equipped with a radio interface, for example, to monitor the activity of the individual devices to allow them to regularly transmit the instantaneous state thereof to a central location.
Another option for monitoring the activity of an electrical device provides for configuring an additional power meter between the power outlet and the power plug of the electrical device. Such devices can recognize whether a connected electrical device is consuming energy in order to infer therefrom an activity of the electrical device.
European Patent Application No. EP 2 278 344 A2 describes a wireless current sensor for taking indirect measurements using magnetic field sensors. In this regard, a plurality of magnetic field sensors are configured around a power supply cable of an electrical device. These current sensors are configured in an enclosure that can be opened to position the current sensor around the power supply line of the electrical device.
There is, therefore, a need for an inexpensive and energy-efficient state detection for an electrical device having a cable connection. There is also a need for a state detection for an electrical device having a cable connection that allows an uncomplicated operation and is simple to install and use.